1. Field of the Invention
The present invention relates generally to wrenches and, more particularly, to a powered adjustable wrench having a sliding jaw.
2. Description of the Prior Art
A powered adjustable jaw wrench having a sliding jaw and a stationary jaw is known in the prior art. As illustrated in FIG. 1, the powered adjustable jaw wrench 10 of the prior art comprises a wrench body 11 including a wrench body member 12 provided with an integral stationary jaw 15, and a handle cover 16, a moveable jaw 17 adjustable relative to the stationary jaw 15. A handle portion 13 and a head portion 14 of the wrench body member 12 form a unitary single-piece part. A worm gear 19 and a sprocket 18 rotatable mounted in the head portion 14 of the wrench body member 12 coaxially with respect to each other. The worm gear 19 is operably connected to a toothed rack of the moveable jaw 17 so that the rotatable movement of the worm gear 19 is transformed into linear movement of the moveable jaw 17.
The prior art powered adjustable jaw wrench 10 further includes a drive mechanism, a motor 22, a sprocket 21, a drive belt 20, and control switch assembly 25, a switch actuator 26, and a power source 27 all housed in the unitary single-piece part wrench body member 12.
As further illustrated in FIG. 2, an exploded view of the prior art detailing the handle portion 13 and the head portion 14 of the wrench body member 12 form a unitary single-piece part. Wrench body member 12 is provided with compartment openings 22, 23 and 24 housing the electric motor 22, the control switch assembly 25 and the electric batteries 27, respectively.
However, the powered adjustable wrenches of the prior art suffer certain drawbacks when utilizing a motor with either pulleys or sprockets and a drive belt or chain respectively, to transmit power to the worm. Because of the friction and forces caused by utilizing belt and chain transmissions, the powered adjustable must be equipped with larger, high torque motors to compensate for the efficiency losses. Thus, prior art wrenches are designed around the motor dimensions and therefore the thickness and size of the wrench becomes dictated by the size of the motor. Prior art wrenches become limited by design to oversized motors to obtain the necessary torque to rotate the worm gear and overcome gravity and friction to carry the weight of the sliding jaw.
Furthermore, the powered adjustable wrenches of the prior art have motors that are not governed and presently experience motor overrun causing vicarious control when adjusting the wrench.